Liquid-air engine



March 24, 1931. E. LANDT LIQUID AIR ENGINE Filed May 8, 1926 w/ m M w Y 7. N. un Nm. j

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Patented Mar. 24, 1931 UNITED STATES ERICH LANDT, F BERLIN, GERMANY 'LIQUID-AIR ENGINE Application filed May 8, 1926, Serial No.

Liquid air has not been used as fuel for power engines because it is difficult to be handled, although with regard to fire danger and dangerous exhaust gases it has great advantages. The attempt to feed liquid air by a sort of lock into a pressure vessel has not been successful probably in consequence of the difficulties arising from the low temperatures.

The invention provides means for the use of liquid air as fuel for power engines and consists therein, that liquid air isbrought in liquid form to the working pressure up to 800 atmospheres and is fed under this pressure to a power cylinder or an interposed pressure vessel, standing under substantially the same pressure. economically7 used for producing power.

A further development of the invention 29 consists therein, that a liquid fuel is injected in the same manner, as the liquid air, into compressed air, especially into the aircompressed inside the cylinder by a compression stroke of an engine, and ignited by the com- 2 pressed air. In this case the working temperature can be chosen so, that the combustion heat of the fuel and the expansion cooling of the liquid air result in mean temperatures at which no difhculties arise from the cooling and heating of both single working methods.

The invention is illustrated in the drawing by way of example on a locomotive'by a longitudinal section.

The fuel tank is a vessel 1 made like the thermos flasks with double walls of metal sheet or wire glass with a vacuum space between the walls and coated inside and outside by aninsulating material 2,V as wood, bakelite, hard paper or felt. An outlet pipe 3, double walled and withan evacuated space between the walls, is attached to the bottom of the vessel 1. The coating felt 2 can be covered on the whole surface with tar or similar tightening materialto make it tighter and safer. The outlet is closed by a cone 4, for example of felt, said cone being connected to a wheel 6 by a spindle 5 made of vulcanized fibre, hard paper or similar heat insulating material. The wheel 6 is placed on a case 7. Said case 7 contains a safety valve 8 with a Hereby the liquid air can bev 107,815, and in Germany May 16, 1925.

spring 9, which is strong through for holding said valve down and prevent splashing of the liquid air even by strongly shaking or upsetting the vessel, while a higher pressure arising inside can escape. One or more holes 10 of the case 7, serving. for letting out the pressure are provided preferably in such a manner, that theyserve as openings for filling the vessel. Y

Directly connected tothe outlet 3 and coated by the heat insulation 11 a pump body 12`is provided in the form of a bored steel block. To thepump body an inlet body 13 is attached, from which two borings lllead into the plunger space. The pump contains two opposed plungers 15 made preferably of a heat insulating material, which needs no special lubricating, as graphite, soapstone or the like, or containing similar intermediate y layers .with the purpose of being able to 70 work in the low temperatures `of the liquid air and to prevent an excessive heat conduction from the driving gear. The double plungers prevent one sided forces', which cause vibrations and deformations of the inlet 8 and might produce leakages. For further keeping off the least cross forces from the inlet 3 the inlet body 13 is connected to `the latter by a Hat tightening junction, consisting ofplane flanges which at cross vibrations allow small sliding movernents of the t connected parts against each other.

ln direct connection to the pump 12 is a pressure ball 16, is provided, which is made of a heat insulating materiah To this valve a space is to be connected, which is to kloe iilled by the vapours of the liquid air. For

' small motors this spaceV can be connected directly to the power cylinder. Y

In the example, shown by the drawing the pump 12 is connected to a power cylinder 18 by interposing a heat' insulation 17 of hard paper or the like. The cylinder contains two pistons`19, 20, running in opposite directions. Hereby the high working pressures can be handled and vibrations are avoided. In the middle of the cylinderl 18 a support 21, is provided as a counterbearing for the valve ball 16 of the pump 12. One piston 2O runs with its cross head like part 22 in an enlargement 23 of the cylinder 1S. To the cross head a rod 24 is connected so as to drive a crank 25 of a shaft 26. An opposite pair of cranks 27 is driven by a pair of rods 28 shown only by the dash and dotted middle line and connected to a cross bar 29 of the second piston 19.

Near the outer ends of the strokes of the pistons 19, 2O outlets 30, 81 are provided, so that the air vapours can escape after expanding. The pistons compress during the return stroke the remaining vapours near to the admission pressure, as the clearance space is made very small, so that a pressure of several hundreds of atmospheres can be attained. The pump plungers l5 are caught on link eyes driven by a gear, similar to the gear of steam engines, in such a manner, that they begin to introduce liquid air 'in or shortly before the inner dead point of the working pistons. ln the described device the working stroke of the plunger l5 may be regulated according to the needed power by any known devices such as a centrifugal regulator or other regulating means. rlhe liquid air evaporates by contact with the cylinder walls and the compressed air and produces useful work during the outward stroke. Heating ribs 32 are extended from the cylinder to the crank case 33 for leading the friction heat from the.

crank gear to the cylinder. The ribs are insulated by the insulating cover 3e.

In the middle of the cylinder 18 a lateral fuel nozzle .35 is provided for injecting fuelV under high pressure into the cylinder.

The motor can thereby be driven, according to the temperatures, as a Dieselmotor with solid injection and ignition by compression, or simultaneously as a high pressure Diesel motor with expansion of liquid air,

'or only as a liquid air engine. Thereby the motor can be driven with any needed powerv and according to any temperature conditions. j p

In'the use of the motor as a combustion engine the opening 3l serves for scavenging and the opening 80 for the exhaust.

The invention intends especially the use of the liquid air motor for driving locomotives, motor cars and water craft and p resents the special advantage that the starting means, the igniting means, the couplings and the change speed gear of the usual combustion motor can be omitted, as the air engines, like the steam engines,` start by themselves and can be highly overloaded.

A great advantage of the new engine consists therein, that instead of the health destroying exhaust gases of the combustion engines the exhaust of the liquid air engine consists of clean air.

Iclaim:

l. A liquid air engine, comprising in combination a working cylinder, an open storage tank for containing liquid air, and mechanically driven means for feeding liquid air from said tank to said cylinder in liquid state against any pressure arising from the evaporation of liquid air.

2. A liquid air engine as claimed in claim l, wherein the clearance space in the Working cylinder is so small with respect to the stroke volume, that the compression attains a value of about hundred atmospheres.

3. A liquid air engine, comprising in combination a Working cylinder, an open storage tank for containing liquid air, mechanically driven, means for feeding liquid air against any pressure arising from the evaporation of liquid air, said feeding means being insulated from said cylinder against heat transmission, and communications connecting the inlet and exhaust of said feeding means to said tank and said cylinder respectively.

4f. A liquid air engine as claimed in claim 3,7wherein the feeding means is a pump constructed in the manner of solid fuel injection pumps with an inlet provided in the wall of the pump cylinders and overrun by the pump piston, and with an exhaust valve opening directly into the working cylinder.

5. A liquid air engine as claimed in claim 3, wherein the feeding means is a pump with two opposed pistons and the pump casing is arranged directly on the tank. j

6. AV liquid air engine as claimed in claim 3, wherein the feeding means is a pump directly attached to the tank by flat flange surfaces in a plane parallel to the direction of movement of the pump piston, so as to not transmit longitudinal oscillations to the tank. Y

7. A liquid air engine, comprising in combination a working cylinder, an open storage tank for containing liquid air, two opposed working pistons in said cylinder, exhaust ports in said cylinder, and mechanically driven means for feeding liquid air from said tank to said cylinderv intermediate said pistons in liquid state against any pressure arising from the evaporation of liquid air.

8. A liquid air engine, comprising in combinationa working cylinder, an open storage tank for containing liquid air, mechanically driven means for feeding liquid air from said tank to said cylinder in liquid state, and means for injecting liquid fuel into said cylinder, the clearance space of said cylinder having such proportion to the stroke volume',y

that a compression is attained up to the ign nition point of the fuel injected.

In. Witness whereof I afHx my si nature.

' Enron LA DT. 

